Preface
Ernest
(Lord) Rutherford, one of the greatest physicists of the last century and the
father of Nuclear Physics, may have put his foot in his mouth when he said;
“Physics is the only real science; all else is stamp collecting”. However greatly such a wild statement may offend non-physicists,
the fact remains that physics is really the mother science around which other
sciences have grown, ‘generating the fundamental knowledge needed for technological
advances that will continue to drive the economic engines of the world’.
If Physics is at the heart
of the sciences, Mechanics, which is essentially a study of different types of
motion of all kinds of material objects in the universe and the forces acting
on them, is really at the heart of Physics. Whether it is the motion of electrons inside
atoms or of atoms and molecules inside matter in any of its states or of the
motion of different parts of any machine or of the planets around a star or of
the growth of plants or animals on earth, motion of an object with reference to
an appropriate frame of reference is perhaps the single most important property
that needs to be studied in great depth.
This is the domain of Mechanics, both the classical and quantum
varieties. A real understanding of
physics is not possible without a deep understanding of Classical Mechanics
where Newton’s laws of motion and their manifold applications play a crucial
role.
A
deep understanding of Mechanics is therefore essential in any physics education
programme at any level, particularly at the undergraduate level where it is a
pre-requisite for understanding other disciplines. Unfortunately, this is not being achieved
adequately for a variety of reasons, especially for want of a rigorous
mathematical approach to learning Mechanics that is so essential for the
application of both in problem solving situations.
The
needs of junior college education in physics are met by a variety of good
curricular materials and outstanding textbooks such as Fundamentals of Physics by Resnick, Halliday and Walker. The situation is not so good when it comes to
undergraduate and graduate levels, primarily because of lack of textbooks
combining a rigorous mathematical approach as stated earlier with a style and
substance that captures the learner’s interest and attention, yet not employing
discouragingly advanced mathematics. It
is in this context that I find great pleasure in introducing and reviewing a
new textbook that has just been published in India and elsewhere by Pearson Education
publishers. The author of this book,
simply titled ‘Mechanics’ (it could as well have been titled ‘Classical
Mechanics’), is a former professional colleague and a great friend of mine,
Professor Somnath Datta.
The Publication
Here
is a picture of the obverse and reverse title pages of Dr Somnath Datta’s book
that is now available in the market:
Containing
14 chapters, two appendices and running to 630 pages, this paper- back
publication was composed entirely by the author himself with the LATEX software
package, thus making the task of the publishers quite easy. A uniquely distinctive feature of the
publication is the presence of a large number of excellent figures/drawings/illustrations
all of them meticulously designed and generated again by the author, and many
of them to realistic scale, using the Gnuplot
package in conjunction with LATEX and the Linux OS. He has explained in some detail how he did
this in the second of the two appendices.
While these are of superb quality, many of them deserve to be printed in
a larger size and on better quality paper to do justice to the effort put
in.
The
following is a somewhat randomly chosen example of the richness and quality of
the illustrations, featuring the scattering of alpha particles by a gold
nucleus plotted precisely to scale.
Incidentally, it is one of the numerous worked-examples in the text and
rather coincidentally focuses on the historic work of Lord Rutherford whom I
have quoted at the very beginning of this post.
The
monumental preparatory work put in by the author, coupled with minor
compromises in the quality of production, has made it possible for the
publishers to offer the book for sale at an unbelievably affordable price. One can have it delivered at home for an
all-inclusive cost of just Rs. 290 (inclusive of an introductory discount of
Rs. 35) anywhere in India by placing an order online at: http://pearson.vrvbookshop.com/book/mechanics-somnath-datta/9788131773734 I have ordered one to be gifted away to a serious student, having already
gone through a complimentary copy given to me by the author very thoughtfully.
The Motivation
In
his own words, Dr Datta’s prime motivation for writing this book is summed up
by the following statement appearing in its Preface:
My
long-standing involvement with teacher-education has shown me the wide gap
between the expected standard (of learning) and reality. I have been concerned about the state of
physics education, especially the level of understanding of students and
teachers at the secondary and higher secondary levels. Misconceptions are widespread. Elementary principles are scarcely
understood. Terms like centripetal and
centrifugal forces have played havoc.
Newton’s third law of motion is totally misunderstood and thoroughly
misinterpreted. Even some textbooks have
the same mistakes.
The
author and I have often shared with each other our serious concern for the
quality of learning with regard to the basic concepts of mechanics and hence of the whole of physics. I have some empirical data to highlight this in
respect of both teachers and students and intend to feature them in a future
blog post of mine. In essence, there
seems to be little difference between the contemporary understandings of the
concepts and those that existed intuitively during the Aristotelian past, even
among many who profess an education in physics.
The Contents
Since
vector algebra and calculus are liberally used throughout the textbook, the
initial chapters are understandably devoted to an exposition of these topics as
preparatory to an understanding of mechanics and the rest of physics as
well. Conservation of linear momentum is
dealt with in chapter 4, followed immediately by Newton’s Second Law of Motion
and its applications. Chapter 6 deals
with the Law of Gravitation (more on this later) followed by Newton’s Third Law
of Motion which the author so rightly describes as ‘totally misunderstood and
thoroughly misinterpreted’. Here he breaks
away completely from the normal style of presentation and develops the concepts though
hand-written drawings forming a slide show that he had developed earlier
specifically for the purpose. In the
same chapter he focuses strongly on the use of free body diagrams and their
problem solving capabilities.
The
concepts of work and energy are dealt with in chapters 8 and 10 interspersed
with chapter 9 dealing with motion under central forces, drawing heavily upon
examples from Astronomy and Space applications.
After describing the properties of fluids, both at rest and in motion in
chapter 11, the focus shifts to systems of particles and rigid body dynamics in
the next chapter. As a prelude to the
last chapter on relativistic mechanics, chapter 13 deals with forces and motion
in non-inertial frames of reference.
The
textbook is embellished with 180 illustrative examples worked out in
considerable detail and about as many end-of-chapter exercises to be attempted
by the student.
Unlike
many other books of its kind, this one does not discuss the very elegant
Lagrangean formulation of mechanics. The
author justifies this by saying that his principal concern has been to put
Newtonian Mechanics on a sound footing and considers such foundation to be of overriding
importance.
Newton and Gravitation
For
me, chapter 6 dealing with the Universal Law of Gravitation is the centerpiece
of the whole textbook because of its wonderful blend of history with the
physics of the phenomenon that literally binds everything in the universe, and
the universe itself, together. The
author sets the stage for it with the following profoundly simple introductory
remarks:
Few
greater tributes have been paid to the genius of Newton who drew upon the work
of his predecessors – Copernicus, Tycho Brahe, Johannes Kepler and the great
Galileo himself – and developed the laws of (classical) mechanics that form one
of the greatest and most enduring edifices of science.
The
author goes on to make an extensive and masterly quantitative and graphical
analysis of the paths of planets
Venus and Mars from both the geocentric and heliocentric viewpoints, draws
relevant conclusions and shows how they eventually led to Kepler’s laws of
planetary motion and subsequently, and even more importantly, to Newton’s law
of Gravitation. The following full page picture
represents the analysis of the path of planet Mars that was to lead Kepler
conclusively to his second law of planetary motion (the figures look better when
enlarged and in the printed version of the book).
For
an article titled, “A Brief History of Gravitation: Copernicus to Newton”
published in the online version of Physics
Education, the reader may refer to:
Other Features
Unlike
conventional textbooks on Classical Mechanics, this book draws its examples
liberally from other areas of physics such as electrodynamics, atomic and
nuclear physics, etc., apart from a distinct bias for astronomy and space
science related examples. This way it
promotes a holistic view of physics as a discipline without artificial
barriers. It also brings out the
absolutely indispensable role of mathematical methods in solving problems in
the world of physics. The consistent and
systematic use of vector methods, often unappreciated by students and teachers,
is especially noteworthy.
The
following is a figure that may appear to have been taken straight out of a textbook
on Electricity & Magnetism, but actually appears under Newton’s Second Law
of Motion in chapter 5 of this book on Mechanics. The motion of a charged particle in an
electric field discussed here and illustrated in such meticulous detail
certainly merits a place in the book which implicitly doesn’t recognize
artificial boundaries or barriers among different areas of physics. Incidentally, the principle finds an
application in conventional TV sets.
The
book is not geared to any specific syllabus of any Indian or foreign university
system, with its content determined by the author’s perception, based on long experience,
of what should go into a useful course on Mechanics in relation to Physics as a
whole. Yet it meets the needs of most
university systems and should be welcomed by any serious student of Physics.
The Author
Starting
with a degree in Civil Engineering in which he obtained considerable
proficiency as exemplified by his technical drawing skills demonstrated in this
book and elsewhere, Dr Datta developed a love for physics and obtained his
doctorate degree from the University of Illinois at Urbana-Champaign. After returning to India, he joined the
Regional Institute of Education (NCERT) at Mysore as a colleague of mine. He chose to retire voluntarily from his NCERT
service and concentrate on teaching of physics at the University of Mysore as a
guest faculty in its post-graduate department of Physics. He has also been involved in the design and
fabrication of a variety of teaching aids and the production of video
programmes for physics education. His
main focus continues to be on his writing efforts and on honing his considerable
artistic talents.
Apart
from his numerous contributions in physics and physics education through
publications in reputed international and national journals, Dr Somnath Datta
is also the author of a book titled “Introduction to Special theory of
Relativity” first published in 1998 by Allied Publishers. He is currently hard at work on another of
his major writing projects, a textbook on Electrodynamics. His numerous friends and I are eagerly
looking forward to its early completion and publication.
Dr
Datta is as devoted to music and performing arts, especially Rabindra Sangeeth and the great dance
dramas of Rabindranath Tagore, as he is to Physics and spends most of his time
on both. One of my earlier blog posts
[See: 11) Tagore and Einstein on Music (Aug
10)] makes a pointed reference to his
musical talents.
The Triumph
The
achievement of writing a book of this high caliber is impressive enough from
any person in any situation. It is much
more so when one realizes that Dr Datta has done this against extraordinary
odds, fighting a long battle against prostate cancer with which he was
diagnosed even before he started writing this book. It is a tribute to his extraordinary and incredible
spirit, courage, and persistence that he has not only carried out his task
successfully but also won the battle against such a deadly enemy. When he visited me last week at my home to
give me the complimentary copy of his book, he appeared as cheerful and normal
as anyone can be. Had I not known about what
he had been going though I would never have suspected that anything was wrong
with him. To me his achievement is as
heroic at the intellectual plane as that of the Marathon Man of Mysore that I
recently wrote about [See my blog post: 54)
Marathon Man from Mysore and his magnificent obsession – Three monumental feats
of endurance and courage (Aug 12)]. I am now pretty sure that it is only a matter
of time before his book on Electrodynamics comes out and I will have the
pleasure of reviewing it as well.
3 comments:
Very well written Sir!
Thanks for sending the online link to buy the book.
I shall share this blog with RIE fb forum.
I must say that i got to know this book at right time. I was preparing for my entrance and quite worried about concepts of mechanics.I will go through this book.Thank u sir.
You can share teaching resources and ideas on TES India too. Excellent piece by the way... : )
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